Môi trường - Ballast water

BALLAST WATERGohoho Emmanuel SenaBallast WaterNecessary to maintain the trim and stability of oceangoing vesselsWhat is Ballast?Ballast is anything used to weight and balance an object.Ships use ballast to maintain balance, stability and structural integrity of the hull.Ballast waterIn the past, ships used solids as ballast; this included metals, sand and rocks.Today, ships use sea water as ballast and it is referred to as ballast water.AQUATIC INVASIVE SPECIES (AIS)Ballast Water and AISAs a result, ships and mariners have unintentionally transferred organisms from one environment to another through the ballast water and sedimentsSpecies are introduced with ballast water discharge in recipient regionsWhat are AIS?Aquatic Invasive Species (AIS) are organisms transported by human activities to a region where they did not occur historically and have established reproducing populations in the wild.Also known as invasive, exotic, alien, introduced, aquatic nuisance species (ANS),nonindigenous species (NIS), non-nativeAdditional FactsNon-native species are considered the second greatest threat to biodiversity after habitat destructionMany non-native species are capable of causing significant ecological, economic or human health impactsIn the marine environment, the rate of new introductions has increased exponentially during the last 200 yearsExample: Overbite ClamCorbula amurensisDetected in SF Bay in 1986Native to AsiaVery high feeding/filtration rateDecline in copepod species associated with spread of clam, may be associated with decline of Delta smeltBallast Water and AISApproximately 7000 species transported around the world each day in ballast water of shipsVolume of global trade is increasing = more ballast water (and species) in movementSpeed of global trade is increasing = more species survive transitExamples of species introduced to SF Bay as a result of ballast water discharge:Palaemon macrodactylusPhiline auriformisTridentiger barbatusVessel FoulingCommunity of organisms that attach or associate with submerged portions of structuresOn vessels, highest density in “niche” areas: sea chests, around rudder, dry dock strips1213Fouling and AISSpecies introduced when organisms fall/drop off structures or spawn (reproduce)EFFECTS OF TRANSFEREcological EconomicHuman health effectsEcological EffectsThe AIS are introduced in some cases on a daily basis. When they become established, they disrupt the native ecology and their presence cannot be reversed.Eg.A non-pacific Sea-star that was introduced in Australian waters threatened commercial shell fish stock like scallops, and in just one estuary in Tasmania, it reached a population of 30 millionEconomic EffectsThe invasive organisms tend to threaten commercial activities like fishing, coastal resources and industrial activities.In the USA, an average amount of $1.8 billion is spent on invasive species annually. Eg.The Zebra mussel which has been transferred into North American Waters, has invaded inland water ways including industrial water uptakes.Between 1999 and 2000, the USA spent $750 million - $1 Billion on the Zebra Mussel alone.Zebra MusselHuman Health EffectsPathogens and diseases are also carried by ballast waterThe dinoflagellates (single-celled marine life) can release toxins which can bloom into red tides and can be absorbed by shell fish. When consumed by humans, this can cause paralysis or even deathHow do they get here?Many mechanisms (vectors) capable of transporting AIS around the worldAquaculture, live seafood shipments, bait, pet store trade, intentional releaseCommercial ships responsible for up to 80% of introductions in coastal habitatsIncludes ballast water and vessel foulingDealing with Ballast WaterThe problem of invasive species is not a pollution problem only, it is also a problem of biodiversity. Hence, a convention on ballast water management has been adopted to deal with the problemInternational Convention for the Control and Management of Ships' Ballast Water and Sediments (BWMC)A diplomatic conference from 9 to13 February 2004 adopted this convention to prevent the potentially devastating effects of the spread of harmful aquatic organisms carried by ships' ballast waterThe Convention will require all shipsTo implement a Ballast Water and Sediments Management Plan. To carry a Ballast Water Record Book To carry out ballast water management procedures to a given standard. Ratification statusThe BWMC will come into force one year after ratification by at least 30 States comprising 35% of the world’s total gross tonnage.As of 12th January 2015, 44 States representing 32.86% out of the requisite 35% of the world’s merchant tonnage have ratified the Convention. The outstanding ratification is expected to be obtained shortly and the Convention will likely enter into force in 2016.Source; ships will the Convention apply to?A ship is defined in the Convention as “a vessel of any type whatsoever operating in the aquatic environment and includes submersibles, floating craft, floating platforms, FSUs and FPSOs”.The Convention will apply to:Ships 400gt and above.Ships from Flag States that have ratified, and ships entering jurisdictions of Flag States.Source; ships will the Convention not apply to?Ships not designed or constructed to carry ballast water,Ships operating only in waters of one member State (unless the member State determines otherwise),Ships of one member State operating only in waters of another member State and the latter authorises an exclusion.Ships which only operate in waters of one member State and on the high seas (subject to conditions).Any warship,naval or State owned ships.Ships with permanent ballast water in sealed tanks not subject to dischargeSource; water treatment system akpe na mi!Questions ?Photo courtesy of the Smithsonian Environmental Research Center